Nutrition is a key issue for healthcare professionals, yet the management of nutritional problems is often poor. Malnutrition is a significant risk for patients in hospital (NHS Quality Improvement Scotland, 2003). A failure to address the issue of malnutrition is a failure of the duty of nurses to protect the health of patients. In a study of 500 admissions to a large teaching hospital, McWhirter and Pennington (1994) found that 40% were malnourished on admission and two-thirds lost weight in hospital.

Nutrition is a key issue for healthcare professionals, yet the management of nutritional problems is often poor. Malnutrition is a significant risk for patients in hospital (NHS Quality Improvement Scotland, 2003). A failure to address the issue of malnutrition is a failure of the duty of nurses to protect the health of patients. In a study of 500 admissions to a large teaching hospital, McWhirter and Pennington (1994) found that 40% were malnourished on admission and two-thirds lost weight in hospital.

Definitions Malnutrition is a term used frequently in healthcare to refer to undernourished individuals who have inadequate intake of energy in their diet. But the term actually refers to any deviation from the normal adequate nutritional requirements for good health. Undernutrition can occur as a result of inadequate intake as well as disorders of digestion or absorption of protein and calories. The term can also be used to refer to deficiencies in the intake of a particular vitamin or mineral. However, with the exception of iron deficiency anaemia, vitamin or mineral deficiencies are more likely to occur in clusters or alongside inadequate intake of protein or calories (Moore, 2001).

Malnutrition resulting from the inadequate intake, digestion or absorption of protein or calories is often referred to as ‘protein-energy malnutrition’. PEM is common and can relate to poor eating habits, social circumstances, acute or chronic illness and disorders of the digestive tract. Acute illness compounded by PEM can lead to increased infection risk, reduced immune response, poor skin integrity, delayed wound healing, increased risk of complications and prolonged hospital stay.

Assessment Nutritional assessment is used to evaluate nutritional status, identify disorders of nutrition and determine which individuals need instruction and/or support (Moore, 2005). An assessment should include screening for malnutrition using a validated tool. It is essential that screening is carried out initially on all patients to identify those in need of further investigation and subsequent nutritional support.

All patients should have the following information recorded as part of their nursing or medical assessment on admission to hospital (NHSQIS, 2003):

This basic information will help nurses to recognise and respond to some of the many issues (such as surroundings, portion size and suitable dietary availability) that can be a cause of PEM in some hospital patients.

Those who are at risk of malnutrition will require more detailed questioning to assess the nature of their risk. The assessment of a patient’s nutritional status should include a general observation of the person, looking for signs of malnutrition, such as the appearance of hair and skin. In a malnourished person hair is likely to be dull, brittle and dry, and there may be signs of hair loss. The skin may be pale, dry and rough, and any wounds will take longer to heal. Nurses should also look for signs of weight loss such as thin appearance and a lack of subcutaneous fat.

The individual’s recent medical and dietary history should also be noted. Dietary history can be used to devise a nutritional treatment plan and recent medical history combined with a dietary history may point to illnesses or conditions that can increase the risk of malnutrition. For example, a patient may report loss of appetite, nausea and vomiting, change in bowel habit, weight loss or tiredness, all of which could be indications of an underlying condition such as cancer.

Assessment tools There is a range of assessment tools available. These include anthropometric measurements, biochemical analyses and specific nurse-administered screening tools, as well as physical assessment and dietary history (see part two of this series). Only a few of these tools have a place in routine nursing practice.

Anthropometric measurements These are measurements of the human body, starting from simple estimates of weight loss, through to ideal body weight, BMI and body composition.

Care must be taken when assessing weight loss using normal weight-for-height assessments as they do not take into account factors such as height loss in old age (Barasi, 2003). In addition, there is a tendency to associate weight gain with fat gain. This may lead to false assumptions about body fat in an individual. For example, those engaging in weight training may gain weight as a result of increased muscle mass.

Weight loss It can be useful to estimate how much weight an individual has unintentionally lost over a period of time because unintentional weight loss is often a feature of serious illness and may be linked to malnutrition.

A weight loss of 5-10% over three to six months is an early indication of risk of undernutrition, while a weight loss of more than 10% indicates a clinically significant risk and the need for nutritional support (Bowling, 2004). Weight loss of more than 20% is considered severe and may require long-term nutritional support (Ward and Rollins, 1999).

Ideal body weight The ideal body weight is a measure of weight in relation to height (Worthington, 2004) and can be calculated using the formula:

Women: 45.5kg (100lb) for the first 1.52m (5ft) of height plus 2.3kg (5lb) for every additional inch.

Men: 48kg (106lb) for the first 1.52m (5ft) of height plus 2.5kg (6lb) for every additional inch.

Body weight should be within 10% of the ideal body weight (Moore, 2005). This method can be used to judge over- or undernutrition (Worthington, 2004) or to set targets for weight gain or loss.

BMI BMI is a useful reliable measure of the appropriateness of weight for height, which is simple to carry out and is well-correlated with body-fat percentage (Shetty, 2003). However, it is used differently in children and adults - in adults it is a height-weight ratio while in children age-related growth and body fat gain must be taken into consideration (Worthington, 2004). BMI should decline before the age of five and then increase through childhood into adolescence until adulthood is reached. Its use is limited in older adults as it does not account for loss of height and loss of muscle mass.

The World Health Organization (WHO) classifies patients into several categories according to their BMI (see Box, below left).

BMI can also be used to assess possible malnutrition. A BMI of less than 16 indicates grade 3 malnutrition, 16-16.9 indicates grade 2 malnutrition, while a BMI of 17-18.4 indicates grade 1 malnutrition (Barasi, 2003).

It should be remembered that while BMI will be high in an obese person, this may mask recent unintentional weight loss that may be associated with illness (Ward and Rollins, 1999). BMI is therefore not a diagnostic tool and other data and information must be considered when assessing nutritional status.

Conclusion Nutritional assessment is and will continue to be an essential part of the nursing role and as nurses we have a professional duty to develop our knowledge and skills in this area.

It is vital that patients who require additional nutritional support be identified quickly in order that the appropriate referrals can be made and nutritional support provided. In the busy healthcare environment the importance of nutritional assessment cannot be underestimated and must not be forgotten.

The second article in this two-part series will look at more specific nutritional assessment tests.

Learning objectives - Define malnutrition and the factors that influence it

- Outline what information should be recorded as part of a nutritional assessment

- Explain how you would calculate unintentional weight loss

- Identify how BMI can be used to assess problems with nutrition

BMI / WEIGHT STATUS Below 18.5 / Underweight

18.5-24.9 / Normal

25-29.9 / Overweight

30-39.9 / Obese

Above 40 / Very obese

Guided learning - Outline your place of work and why you were interested in this article

- Describe the last time you encountered a malnourished patient

- Identify information in this article that could have helped you in the care of that patient

- Explain how you intend to disseminate what you have learnt among your colleagues